In article ,
Lew Hartswick wrote:

syoung wrote:

Bill Janssen wrote:

Ivan Vegvary wrote:

Okay, so the switch from 6 volts to 12 volts (automobiles) was made
to save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I
understand that a few military vehicles and commercial trucks are 24
volts. Why not our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

Autos are going to use 34 volts in a couple of years. They are being
designed now.

Bill K7NOM

Was supposed to 42 volts several years back - what happened?

POSSIBLY: The NEC limit on "safe" voltage level. ?????

Has to be at least 48 volts, or telephone wires would have to be handled
as power, not signal, wires. And ring power on telephone lines is 100
volts 20 Hz riding on top of the -48 volts DC.

One can measure the 48 volts across any telephone pair with no off-hook
telephones. When a phone is taken off-hook, the voltage drops to about
6 volts.

Phantom power in microphone circuits is also 48 volts DC.

Joe Gwinn